The invention relates to safety stirrups and more particularly to the type of safety stirrup that has a swingaway footrest bar which is normally held in a foot supporting position, bridging the lower ends of the stirrup side bars, and is released by excessive upward tilting of the rider's boot toe, which is anticipated to occur when a rider falls or is thrown from a horse.
It has long been known that horseback riders face a dangerous risk of one of their booted feet becoming entangled in a stirrup when thrown by or accidently falling from a horse. The conventional stirrup, including its rigid, steel hoop, does not always slip off the rider's boot during a fall, and, of course, if the foot remains held by a stirrup, and the horse bolts or continues to run, resulting injuries to the rider can be severe and possibly fatal.
In light of this long known danger, there have been numerous prior efforts to develop a stirrup that functions in the usual manner during normal riding conditions, and that releases automatically in reaction to abnormal pressures exerted by tilting or rotation of the rider's boot associated with a fall. Previous attempts to design a safety stirrup have not been widely accepted. One common shortcoming of prior safety stirrups has been their complexity and the resulting, excessive manufacturing cost. Examples of overly complex, prior art safety stirrups include those disclosed in U.S. Pat. No. 1,392,673 issued to Baker, U.S. Pat. No. 1,062,125 issued to Sipes, and U.S. Pat. No. 545,796 issued to Haddorf and Eggers.
Other prior art safety stirrups may have been simpler to manufacture, but on the other have have not provided the high degree of reliability and durability demanded of such a safety device. For example, in U.S. Pat. No. 358,603 issued to Gibson, a relatively simple stirrup mechanism is disclosed in which the side bars of the stirrup are pivotally joined so as to be forced apart by the boot of a falling rider, which thereby effects a release of a catch normally retaining the lower end of one side bar connected to the adjacent end of the footrest bar. But, the forces needed to spread the side bars in the Gibson patent do not always result from the displacement of the rider's boot that can be expected from a fall. Normally, the boot of a falling rider will tilt about a pivot at the footrest bar, with the toe of the boot being forced upwardly and the heel downwardly, and/or turned to the side with the toe being forced into or away from the side of the horse. The resulting movement of the boot does not insure that the side bars in the Gibson stirrup will be forced outwardly, as needed to release the footrest bar. Moreover, the one end of the Gibson footrest bar is rigidly and integrally joined to one of the side bars such that the rider's boot may still become wedged between the top of the stirrup hoop and the rigidly affixed footrest bar, even though the pivotally mounted side bar has been released and has swung outwardly.
In another type of safety stirrup, as exemplified by U.S. Pat. No. 933,958 issued to Carter, an upwardly actuated trip lever is disposed beneath the strap receiving hanger bar, so as to be triggered by a displacement of the rider's boot. It is designated such that the instep of the boot presses upwardly against the trip lever at the top of the stirrup. However, if the toe of the boot turns to the side of the stirrup during the rider's fall, the boot could still hang up in the stirrup without actuating the trip lever. Another example of this type of safety stirrup is disclosed in U.S. Pat. No. 475,374 issued to Anderson.
In still aother type of safety stirrup, the disposition of the trip mechanism is such that it is intended to be upwardly actuated by the boot, as above. However, this placement of the trip lever does not take into account the most likely movement of the boot, namely the above-mentioned upward tilting of the rider's toe, pivoting about the footrest. The resulting force on the trip lever is askew to the movement of the lever, thereby increasing the probability of the trip lever jamming and failing to release the rider's boot. U.S. Pat. No. 898,683 issued to Riley and U.S. Pat. No. 1,276819 issued to Sklar show versions of this type of stirrup in which the trip lever is mounted for upward travel between the side bars of the stirrup.
Accordingly, it is an object of the invention to provide a safety stirrup that will reliably release the rider's boot under every possible, abnormal orientation of the rider's boot that might occur during a fall and yet not inadvertently release under normal riding conditions, and that is durable under the environmental conditions associated with horseback riding, and that is composed of a few number of readily producible and easily assembled components so as to be capable of mass manufacture at a relatively low per unit cost relative to other safety stirrups of comparable reliability and durability.